How to choose a case for your PC

Hardware enthusiasts will pore over the specifications of a new system, carefully weighing up processors, chipsets and storage, but whether you’re buying a pre-built system or assembling your own, there’s one aspect that often gets neglected: the case.

Beyond its basic appearance, many of us rarely give the case another thought – it is after all just a box in which to house the really important stuff and, besides, we’ll probably hide it under a desk anyway. But the case plays a vital role in the smooth running of a PC, along with future expansion.

In this article I’ll be looking at the various options available in today’s PC case market and what to look out for. Looks are, of course, important, especially for media or home theatre PC (HTPC) cases, but there are plenty of other aspects to be aware of, any of which can mean the difference between a happy system and one that will cause problems, even before switching it on.

Respected manufacturers of cases include Akasa, Antec, Coolermaster, Lian Li, Silverstone, Thermaltake and Zalman, and like everything in life, you get what you pay for. While there are a few respectable cases costing less than £100, you should aim to spend between £100 and £150 for a decent general-purpose model. Higher quality or specialist models can exceed £200, and if you want one with a colour touchscreen for a top-end media PC, you’re looking at £400 to £500.

Size matters
The most obvious specification when choosing a PC case is of course its size. Most cases are defined as either Desktops or Towers depending on whether they lie flat or stand up, with Towers typically available in Mini, Mid or Full sizes.

Then there are the really compact cases, which are generally known as Small Form Factors (SFF). Alternatively some cases are simply described as being suitable for a certain motherboard form-factor, such as ATX, Micro-ATX or Mini-ITX.

The motherboard size is initially the most important consideration for a case, and if you have an ATX board, you’ll obviously need an ATX-compatible case. Don’t blindly rely on form-factor compatibility alone though: look up the dimensions of your board and make sure the case will accommodate it. Small variations in board sizes can cause real issues with smaller cases, especially those designed for media or HTPCs.

Beyond board size, the main difference between most small, medium and large cases is the number of drives they’ll accommodate. Case manufacturers quote numbers of drive bays for both 3.5in and 5.25in drives. But again, don’t assume a case with four 3.5in drive bays will take four hard disks.

Hard disks run hot and to avoid an early demise, they need decent airflow. The best cases will leave space around hard disks in each drive bay, but many don’t, and if you were to fully occupy all their bays with disks, they would literally be right on top of each other. If the 3.5in drive bays don’t have any space between them, you’d be advised to leave every other bay empty when fitting hard disks – so a four-drive case on paper could be a two drive case in reality.

How many bays do you need? That of course depends on your current configuration and plans for future expansion. Many PCs have just one or two drives, but if you’re into Raid, you’ll need to accommodate many more. Remember though that spare 5.25in bays can also be used to house 3.5in drives with appropriate brackets.

Beyond the motherboard and drives, there are other components to be aware of. The desire for quieter systems is driving bigger and bigger heatsinks, and the largest models may not have the required clearance for airflow in a smaller case, or even allow a large heatsink to fit into it in the first place. Heatpipes curving round the top of graphics cards can also cause clearance issues.

Long expansion cards are increasingly rare, but if you have any, be sure there’s room to accommodate them. Smaller cases may not even allow a full-sized ATX power supply. So when choosing a case, be sure it’ll fit all your components with ease, while also supporting future expansion.